Good to talk to you again. I have Fulves 1996 'Blocking Off' manuscript. He tells the story of a session with Scarne in 1976 I think in which Scarne tips his version of the Stevens. He states that this was the method used to fool Rothstein et al. Fulves does say that in Scarne's hands this move was very deceptive. Praise indeed from a magician who employs high standards to this type of riffle cull. Also, people on this forum have reported seeing Scarne do an ace cutting routine on TV that seems to meet some of the conditions described by Scarne in his ace cutting for Cardsharks.
In spite of this, I still harbour serious doubts. There are at least three accounts of this Rothstein encounter from Scarnes shamelessly self promotional autobiography, 'The Amazing World of John Scarne' his 'Scarne on Cards' and 'The Odds Against Me'. The description of the handling differs in significant ways in each of these accounts and there is no corroborative evidence that Scarne actually met Rothstein. Harry Lorraine was asked on the Cafe whether he has seen Scarne's ace cutting feat and Harry replied in wonderfully and typically direct way,
"Of course I did, John. I was not as impressed as laymen or many magicians were. There are much, much, better versions of cutting the aces now."
This is hardly a ringing endorsement for the method.